Question: What position was occupied by John A. Macdonald and is now held by Alexander Mackenzie?
Paraphrase: What function used to be occupied via John A. Macdonald and is now held through Alexander Mackenzie?
SPARQL (Wikidata): SELECT ?answer WHERE { wd:Q128702 wdt:P39 ?answer . ?answer wdt:P1308 wd:Q128708}